Screen-based behaviors in Australian adolescents: Longitudinal trends from a 4-year follow-up study.

The longitudinal trends of screen time, a highly prevalent behavior in adolescents, are relatively unknown. This study examined longitudinal trends in screen time among a large sample of Australian primary school-aged children transitioning into secondary school-aged adolescence. Data were derived from the Longitudinal Study of Australian Children (LSAC). In 2010, 2179 children (49.7% boys; 10.3 ± 1.1 years) completed a time-use diary, recording their main activities during waking hours. This was repeated with the same sample in 2012 (12.4 ± 0.5 years) and 2014 (14.4 ± 0.5 years). Data were analyzed for time spent in TV viewing, computer use, electronic gaming, and social networking and online communication. Repeated-measures MANCOVA tests were performed to analyze trends in screen time. Trends were also analyzed by sex. Total screen time significantly increased (+85.9 min/day) over four years (ηp2 = 0.010, P < .001), but differed by sex, with a larger increase in boys (boys: +41.6, girls: +22.7 min/day). Electronic gaming increased in boys (+43.2 min/day) and decreased in girls (-16.8 min/day). In contrast, girls reported larger increases in TV viewing (boys: +0.4, girls: +29.1 min/day), computer use (boys: +24.8, girls: +34.3 min/day) and time communicating online and social networking (boys: +4.3, girls: +15.2 min/day). To conclude, screen time among adolescents increases between the ages of 10 and 14 years, but differs by sex and screen time domain. Future screen time reduction interventions may choose to focus on recreational computer use and electronic gaming in boys and TV viewing and time spent communicating online and social networking for girls.